1. Field of the Invention
The present invention relates to an optical system, and more particularly to a miniaturized optical system for taking image used in a camera mobile phone.
2. Description of the Prior Art
In recent years, with the popularity of camera mobile phone, the optical system for taking image has been becoming thinner and thinner, and the photosensitive assembly of a general digital camera is nothing more than CCD (charge coupled device) or CMOS (Complementary Metal Oxide Semiconductor). Due to the advancement of the semiconductor technique, the pixel size of photosensitive assembly has been being reduced continuously, and the development of the miniaturized optical system for taking image is toward the high resolution field. Therefore, the demand for the image quality becomes increasingly urgent.
A conventional mobile phone's lens assembly usually consists of three lenses: from the object side to the image side: a first lens element with positive refractive power, a second lens element with negative refractive power and a third lens element with positive refractive power, thus forming the so-called type of Triplet. Although such type of triplet can correct most of the aberration produced by the system, and the field of view is quite extensive, the demand for the total optical  height is bigger. Thereby the demand for the conventional structure is bigger, which is inapplicable to a more miniaturized optical system for taking image.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.